The present invention relates to a discrete step rotary actuator, comprising a stationary portion or stator, a rotary portion or rotor and means for rotating the rotor with respect to the stator.
Electric actuators of the type referred to, also known as step-by-step motors or steppers, are used in applications requiring an accurate angular shift of the rotor.
The operation of such actuators or motors, usually with a permanent magnets, with variable reluctance or of hybrid type, provides that a series of current pulses, according to a given sequence, is sent to the actuator, so as to shift the rotor by consecutive jogs, until a balance position is obtained. It is thus possible to rotate a shaft associated with the rotor in the desired position and at the desired speed, by simply counting pulsing and setting their frequency, since the balance positions of shaft and rotor are determined mechanically with a high accuracy.
Known step-by-step actuators are usually bulky and require complex electronic driving circuits, generally digital circuits. The typical jogging operation of said actuators further results in vibrations and noise, above all at low speeds and when simpler driving techniques are used.